I was able to load up a handful of free instruments off the net today and I have to say that this is a really great feature for this already great synth. Being able to throw new samples into a patch opens up a tremendous amount of sonic possibilities. I understand ROLI support doesn't want to deal with having to help people with this, but it is too bad that more people don't know about it. If we had a unified user base all legally sharing sfz instruments that are formatted properly, that would be a pretty amazing thing.
One thing that would be really nice if ROLI is still considering working on this functionality, would be if Equator could work with sfz files that list notes by pitch (ex. C#2) in addition to MIDI number (ex. 37) which looks to currently be the only acceptable format. There are quite a few instruments I found that provide sfz files with the pitch format only. With some of the higher quality instruments the time it would take to get all of the pitches converted to numbers is not insignificant. I decided to skip them for now and may take it on as a project later but honestly I would rather spend time creating music.